Two desktop.ini files have appeared by themselves on my desktop as well as in other folders e.g.

C:\Program Files

Libraries\Documents

I am highly suspicious of these files as my computer seems to be running slower than it normally does, and is very slow to start up. When I log in to Windows 7 before loading the start-up screen it goes black for about 2 minutes before it appears. My issue seems to be very similar to this discussion(https://community.mcafee.com/thread/66993?tstart=0), however I am convinced I have a virus on my computer.

This issue follows from my McAfee virus scan finding two Artemis! issues which I posted about two days ago (https://community.mcafee.com/thread/75058). After being told that artemis!C649BD38C313 was a legitimate file and I could restore it, I am again highly suspicious of it because it has shown up again in my virus scan. This is very similar to the circumstances affecting michaelm2 in the discussion noted in the previous paragraph. He also ran a scan showing an artemis a couple of days before two desktop.in files appeared on his desktop.

What I have done to try and remove the virus

I have also read this discussion (Re: Desktop.ini) and have done the following to try and remove the virus:

Ran a full scan of McAfee with the latest updates -this returned artemis!C649BD38C313, which again could not be quarantined

Ran Stinger -no virus's were found

Ran Malwarebytes Anti-Malware -which found a bunch of suspicious programs which I quarantined.

These actions don't seem to have fixed the issue has my desktop is still showing the desktop.ini files. Any help on this issue would be greatly appreciated.

The first Removal Guide should also remove the (Pup.Optional.Default Tab.A) as well. For it basically utilizes the same Tools. However should it be the case it does not, The following Removal Guide additionally uses the "Junkware" Removal Tool :Remove PUP.Optional.DefaultTab (Removal Guide)

I noticed you said you had "Quarantined" the Detections? I recommend Selecting them all to be removed/Restart.

I tried to submit the Artemis, but it failed to submit. Can you please confirm I did it correctly? I went to "Quarantined and Potentially Unwanted Programs", selected the Artemis, then clicked "Send to McAfee".

Your screenshot shows that it detected both "Search Protect/Default Tab as well. Please Delete/Remove/Restart to remove all remnants. As for submitting the Artemis! detections, please refer to this thread on how to submit.